Coil for removing heat from a lamp through direct contact coolant flow

ABSTRACT

A fluoropolymer coil is adapted to be wrapped around a lamp, such as a high intensity discharge (HID) lamp, and adapted to have a coolant, such as water, flowing through the coil. The coil can cool the lamp, provide improved lamp life expectancy, and allow the lamp to be kept closer to a plant canopy when the lamp is used in hydroponic applications, for example. The coil provides direct contact with the lamp to remove heat through conduction while not subjecting the lamp to high temperatures as other units that envelope the lamp. The coil may discourage algae growth while not significantly reducing the light emitted from the lamp and through the coil. The coil is lightweight, requires no cleaning or adjusting or o-ring replacement, and can work with most hoods in the hydroponics industry, not requiring its own special hood or fixture.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application claims the benefit of priority of U.S. provisional patent application No. 61/516,060, filed Mar. 29, 2011, the contents of which are herein incorporated by reference.

BACKGROUND OF THE INVENTION

The present invention relates to lamp temperature control methods and systems and more particularly, to a coil having coolant flow therethrough that removes heat from a lamp through direct contact.

High intensity discharge (HID) lamps generate significant heat that may damage or limit the life expectancy of the lamp and/or other lighting components if the heat is not removed. In the field of hydroponics, these lamps are often used to provide growth lighting for plants. However, with high heat generation, these lamps are usually kept a safe distance away from the plant canopy.

Existing systems contain the lamp inside of a borosilicate tube which is subject to intense heat. Water around the tube is used as a method of absorbing heat. Keeping in mind that the lamp is constantly contained in a sealed heat envelope, this method of so-called heat removal is actually diminishing the life of the lamp by exposing it to intense heat inside of its enclosed cylinder.

As can be seen, there is a need for an improved method and system for removing heat from a lamp while maximizing its life expectancy.

SUMMARY OF THE INVENTION

In one aspect of the present invention, a lamp cooling system comprises a tubing coil adapted to fit around and in contact with a lamp, the tubing coil providing a coolant flow path therewithin; and a pump adapted to move a cooling fluid through the coolant flow path via coolant tubing connected to the tubing coil.

In another aspect of the present invention, a method for cooling a lamp comprises wrapping a fluoropolymer coil about the lamp, providing direct contact between the lamp and the coil; and flowing coolant through the coil during operation of the lamp.

These and other features, aspects and advantages of the present invention will become better understood with reference to the following drawings, description and claims.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a perspective view of a direct contact water cooling coil according to an exemplary embodiment of the present invention;

FIG. 2 is a side view of the direct contact water cooling coil of FIG. 1, showing coolant flow through the system;

FIG. 3 is a cross-sectional view of the direct contact water cooling coil taken along line 3-3 of FIG. 1; and

FIG. 4 is an exploded view of the direct contact water cooling coil of FIG. 1.

DETAILED DESCRIPTION OF THE INVENTION

The following detailed description is of the best currently contemplated modes of carrying out exemplary embodiments of the invention. The description is not to be taken in a limiting sense, but is made merely for the purpose of illustrating the general principles of the invention, since the scope of the invention is best defined by the appended claims.

Broadly, an embodiment of the present invention provides a fluoropolymer coil adapted to be wrapped around a lamp, such as a high intensity discharge (HID) lamp, and adapted to have a coolant, such as water, flowing through the coil. The coil can cool the lamp, provide improved lamp life expectancy, and allow the lamp to be kept closer to a plant canopy when the lamp is used in hydroponic applications, for example. The coil provides direct contact with the lamp to remove heat through conduction while not subjecting the lamp to high temperatures as other units that envelope the lamp. The coil may discourage algae growth while not significantly reducing the light emitted from the lamp and through the coil. The coil is lightweight, requires no cleaning or adjusting or o-ring replacement, and can work with most hoods in the hydroponics industry, not requiring its own special hood or fixture.

Referring now to FIGS. 1 through 4, a cooling system 10 may include a fluoropolymer coil 14 adapted to wrap around a lamp, such as a high intensity discharge lamp 12. The fluoropolymer 14 may be formed from one of or a mixture of fluoropolymers, such as polytetrafluoroethylene (PTFE), fluorinated ethylene propylene (FEP), perfluoroalkoxy fluoropolymer (PFA), perfluoromethylvinylether (MFA), polyvinyledenefluoride (PVDF), and the like. In some embodiments, the fluoropolymer coil 14 may be made from FEP.

A lamp socket 18 may be used to mount the lamp 12. A coil assembly 16 may include end plates 24 disposed on each end of the coil 14. Threaded rods 22 may interconnect the end plates 24, while nuts, such as wing nuts 20, may be disposed on each end of the threaded rods 22. Typically two threaded rods 22 may be used.

A barbed fitting 26 may be disposed on a cooling coil input 46 and a cooling coil output 48 to connect coolant supply tubing 42 and coolant return tubing 44 thereto. Typically, the coolant used in the system 10 may be water.

A pump 28 may be used to flow coolant through the coil 14. The pump 28 may include a chiller portion to chill the coolant as may be required to maintain proper operating temperature of the lamp. Barbed fittings 30, 32 may be used to connect the tubing 44, 42 to the pump 28.

A safety flow switch 34 may be installed along the coolant return tubing 44. As coolant exits the coil 14, it may flow through the safety flow switch 34. Barbed fittings 36, 38 may be used to connect the tubing 44 to the safety flow switch 34. Wiring 40 may be used to provide power to the safety flow switch 34. An electrical outlet may be provided on the safety flow switch 34. Typically, this outlet may be used to plug in a power source for the lamp 12.

A time delay may be programmed into the safety flow switch 34 such that coolant is required to flow through the safety flow switch 34 for a predetermined period of time before power is supplied to the lamp 12. The safety flow switch 34 may also cut power from reaching the lamp 12 if the flow of coolant through the system 10 stops. Once coolant flow has been restored, the safety flow switch 34 may go through the time delay (as described above) before turning the lamp back on. The safety flow switch 34 may include a time delay to protect the lamp 12 from short cycling if power is interrupted to the system 10.

The coil system 10 of the present invention has been tested. Temperature readings were taken about 3.5 inches away from a 1000 watt HPS lamp using a 25 gallon reservoir for coolant and an Eco 396 pump. The measured temperature remained at 85 degrees for over 1 hour, with little or no increase in temperature. After running the coil system 10 for two hours, an increase in temperature of the reservoir water increased from 78 degrees to 88 degrees. It should be noted that no chiller was used in this test.

The decrease in lumens was minimal, typically less than 10 percent. However, due to the fact that the lamp may be kept closer to a plant canopy (as compared to warming running conventional lamps), the decrease in lumen output may not be relevant.

The coil may be made from a fluoropolymer that may resist algae growth while being able to be in direct contact with the lamp. Other materials may be used for the coil, depending on application. The coil may be extruded such that the coil is shaped similar to the lamp onto which it is designed to be used, providing a coils that resiliently contacts the lamp when installed.

It should be understood, of course, that the foregoing relates to exemplary embodiments of the invention and that modifications may be made without departing from the spirit and scope of the invention as set forth in the following claims. 

1. A lamp cooling system comprising: a tube geometry adapted to fit around and in contact with a lamp, the tube geometry providing a coolant flow path therewithin; and a pump adapted to move a cooling fluid through the coolant flow path via coolant tubing connected to the tube geometry.
 2. The lamp of claim 1, wherein the tube geometry is tube coil.
 3. The lamp cooling system of claim 1, further comprising first and second end plates disposed on each end of the tube geometry.
 4. The lamp cooling system of claim 3, further comprising threaded rods extending between and connected to the first and second end plates.
 5. The lamp cooling system of claim 1, wherein the tube geometry is a fluoropolymer coil.
 6. The lamp cooling system of claim 1, further comprising a safety switch disposed in series with the coolant tubing.
 7. The lamp cooling system of claim 6, wherein the safety switch includes a switch to disconnect power from the lamp when a lack of coolant flow through the coolant tubing is detected.
 8. The lamp cooling system of claim 6, wherein the safety switch includes a time delay mechanism that delays sending power to the lamp until coolant flow over a predetermined period of time is detected.
 9. The lamp cooling system of claim 6, wherein the safety switch includes a delay to prevent short cycling of the lamp.
 10. A method for cooling a lamp, comprising: wrapping a fluoropolymer coil about the lamp, providing direct contact between the lamp and the coil; and flowing coolant through the coil during operation of the lamp.
 11. The method of claim 10, further comprising controlling power supplied to the lamp with a safety switch, the safety switch starting the lamp after detecting flow through the coil for a predetermined period of time, the safety switch disconnecting power to the lamp if flow through the coil stops, and the safety switch providing a delay to prevent short cycling of the lamp. 